Deno

EU VAT validation in Deno

Validate EU VAT numbers in Deno using the built-in fetch API and TypeScript. Deployable to Deno Deploy with zero configuration — no npm install, no package.json needed.

Implementation steps

1
Use Deno's built-in fetch — no imports needed for HTTP
2
Load the API key from Deno.env or a .env file
3
Define a TypeScript interface for the VATResult response
4
Run with --allow-net --allow-env or deploy to Deno Deploy

Code example

Deno (TS)

// deno run --allow-net --allow-env validate_vat.ts
// Deploy to Deno Deploy — no npm install, no config

interface VATResult {
  valid: boolean;
  status: string;
  company_name?: string;
  company_address?: string;
}

async function validateVAT(
  country: string,
  vatNumber: string
): Promise<VATResult> {
  const res = await fetch(
    `http://localhost:3000/api/v1/validate/${country}/${vatNumber}`,
    { headers: { Authorization: `Bearer ${Deno.env.get("TAXID_API_KEY")}` } }
  );
  return res.json() as Promise<VATResult>;
}

const result = await validateVAT("DE", "DE123456789");

if (result.valid) {
  console.log(`Valid EU business: ${result.company_name}`);
} else if (result.status === "service_unavailable") {
  console.warn("VIES temporarily unavailable — retry later");
} else {
  console.log("Invalid VAT number");
}

cURL

curl "http://localhost:3000/api/v1/validate/DE/DE123456789" \
  -H "Authorization: Bearer $TAXID_API_KEY"

# {
#   "valid": true,
#   "status": "active",
#   "company_name": "Example GmbH",
#   "company_address": "Musterstraße 1, 10115 Berlin",
#   "cached": false
# }

API response

The TaxID API returns a consistent JSON response for every validation request:

200 OK (active)valid

{
  "valid": true,
  "status": "active",
  "country_code": "DE",
  "vat_number": "123456789",
  "company_name": "Example GmbH",
  "company_address": "Musterstraße 1, 10115 Berlin",
  "request_date": "2026-05-10T00:00:00.000Z",
  "cached": false,
  "request_id": "req_01j..."
}

Error handling

The API uses a consistent Stripe-style error format. Always handle service_unavailable separately — VIES has occasional downtime and you should not reject valid customers during outages.

active

VAT number is valid and the business is registered

invalid

VAT number format is wrong or not registered in VIES

service_unavailable

VIES or the national system is temporarily down — retry later

Evaluating EU VAT APIs? Compare TaxID vs Vatstack, Vatlayer, Avalara →

Ready to implement?

Get your free API key and start validating EU VAT numbers today.

Get free API key

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